Aircraft breathing regulator



July 9, 1946. G. M. 'DEMING v 2,403,508

AIRCRAFT BREATHING REGULATQR Filed Jan. 26, 1943 5 Sheets-Sheet 1 7'0 BREATHING Mas/r INVENTOIR. ewye M 06297227;

A TTORNE Y5 J y 1946. G. M. DEMING 2,403,508 v AIRCRAFT BREATHING REGULATOR Filed Jan; 26, 1943 5 Sheets-$heet 2 INVENTOR.

A TTOI-PNEYS y 9, 1946- G. M. DEMING AIRCRAFT BREATHING REGULATOR Filed Jan 26, 1945 s Shgets-Sheet s INVENTOR. G'emfye M Demz'ny j flw, 2 4%;,

A TTORN E YS y 1 5- G. M. DEMlNG AIRdRAFT BREATHING REGULATOR Filed Jan. 26, 1943 5 Sheets-Sheet 4 1 INVENTOR.

George 4% Deming BY a; 0, AWLEM ATTORNEYS Patented July 9, 1946 2,403,508 AIRCRAFT BREATHING REGULATOR George M. Deming, Orange, N. J assignor to Air Reduction Company, Incorporated, a corporation of New York Application January 26, 1943, Serial No. 473,627

18 Claims.

This invention relates to breathing apparatus for supplying oxygen to aviators, and more particularly to improvements in an oxygen regulator of the so-called demand type, that is, the type in which the oxygen is supplied only in response to inhalations by the aviator.

The type of oxygen regulator to which this invention relates in particular has two stages of pressure reducing mechanism for the incoming oxygen. The first-stage oxygen regulating valve admits oxygen to a first-stage chamber and is controlled by a diaphragm forming one wall of this chamber. The second-stage regulating valve admits oxygen from the first-stage chamber to a second-stage chamber and is controlled by a second diaphragm which forms one wall of the second-stage chamber and which is exposed at its outer side to atmospheric pressure. The oxygen passes from the second-stage chamber through a port into a respiratory chamber, or mixing chamber, communicating with the breathing mask. Outside air is admitted to the mixing chamber through a second port. The oxygen and air ports leading into the mixing chamber are controlled by oxygen-proportioning and air-proportioning Valves which in turn are controlled by an aneroid device so that the oxygen concentra-' tion in the gas breathed by the aviator is varied automatically in accordance with altitude requirements. The regulator supplies air with no oxygen enrichment at sea level. and for relatively low altitudes up to say 5,000 feet, and a mixture of oxygen and air from that altitude up to say 33,000 feet, the concentration oi. oxygen gradually increasing as the altitude becomes higher. Around 33,000 feet the air-proportioning valve fully closes so that at this altitude, and higher altitudes, only oxygen is breathed by the aviator.

Among the objects of this invention are to improve th construction and operation of an oxygen regulator of the type above described; to make it compact in construction and of light weight; to insure an adequate oxygen concentration in the gas mixture at the intermediate altitude as well as the higher altitudes; and to provide certain improvements which are desirable and useful not only in an oxygen regulator of the kind above described but in other regulators as well; and in general to provide a more satisfactory oxygen-regulator.

In accordance with the invention the parts of the regulator are so constructed and related, par-- ticularly the two stages of the pressure reducing mechanism for the oxygen, as to make for compactness and reduction in size of the apparatus.

The second-stage oxygen regulating valve is constructed in a novel manner to overcome certain disadvantages of the corresponding valve in previous oxygen regulators and to improve its operation and the operation of the oxygen regulator as ,a whole. The oxygen-proportioning and airproportioning valves are mounted and correlated in an improved manner, and each of these valves is so constructed that the danger of insumcient suction in the mixing chamber for intermediate altitudes, and hence a too low concentration of oxygen in the gas mixture for such altitudes, is

avoided. There is an automatic oxygen by-pass valve for admitting extra oxygen from the second-stage chamber to the mixing chamber when occasion demands, as hereinafter described, and an emergency by-pass controlled by a hand-operated valve connects the oxygen inlet with the mixing chamber. The oxygen regulator is also provided with manually operable control means which may, be actuated by the aviator either to render effective the mechanism for automatically mixing the oxygen and air in accordance with altitude requirements, or to render it ineffective and simultaneously close the air-proportioning valve and full open the oxygen-proportioning valve, and at the same time mechanically open the above-mentioned automatic oxygen by-pass valve.

An oxygen regulator constructed in accordance with the invention and embodying the various features above referred to is illustrated in the accompanying drawings, in which:

Figure 1 is a diagrammatic representation of the oxygen regulator, and Figs. 2 to 10 inclusive illustrate one form of the regulator as actually l constructed;

Fig. 5 is a horizontal section taken on the line 55 of Fig. 4;

Fig. 6 is a rear view looking into the respiratory chamber, or mixing chamber, the casing portion shown in Fig. 4 which is normally fastened to the rest of the casing at the rear of the mixing of a clamping ring 5 and the bolts 3 chamber being removed to expose to view the mechanism within the mixing chamber;

Fig. 7 is a detail view of the manually operable mechanism for rendering either effective or ineflective the mechanism for automatically mixing in the. line 8-8 of row In in Fig. 2, the diaphragm which forms one wall of this chamber being removed to expose to view the mechanism within the chamber.

Before proceeding with a detail description of the oxygen regulator it, should be explained that Figs. 2-10 illustrate one type of regulator as actually constructed but these figures are drawn to an enlarged scale and it should be understood that the regulator is much smaller in size than they indicate. The diagram of Fig. l is included so that the description of Figs. 2-10 will be easier to follow. Some liberties had to be taken in diagrammatically representing the construction and relationship of the various parts but in most respectsFi'g. 1 is in conformity with the other figures. Parts referred toin the description but not found in Fig. 1 will be found in the other figures.

The main casing of the regulator comprises two hollow cylindrical sections a and 17 adapted to be clamped together by means of bolts I (Fig. 2) with an annular gasket 2 interposed between them.

The section a has an integral inner or front wall 3. The annular opening at the rear of the section a is closed by a diaphragm 4 clamped to the cylindrical walls of this section by means The bolts (only one of which shows in the drawings) pass through bolt holes in the clamping ring 5 and the diaphragm, loosely through bolt holes in bosses 6 formed on the inner surface of the cylindrical walls of the section a (Fig. 4), through openings in the gasket 2, and then into threaded openings in bosses B at the inner surface of the cylindrical walls of the section b (Fig. 6), thus clamping all these parts together. The cylindrical walls of the section a and its inner wall 3 and the diaphragm 4 form an enclosure which constitutes the first-stage oxygen chamber S1. Oxygen isadmitted to this chamber through an inlet 1 provided with a suitable filter screen 8. It then passes through a port 9 commanded by the first-stage regulating valve l0. One end 'of a valve rod projects into a recess in the body of the valve l (Figs. 2 and 4) and the other end of the valve rod projects into a recess in one arm 12 of a bell-crank 1ever.. This bell-crank lever is mounted to swing about the axis of a pivot pin' l3 (Fig. 4) which has a bearing at one end in the inner wall 3 of the casing section a, and at its other end in a bar I4 supported in spaced relation to the wall 3. The other arm II of the bell-crank lever is connected by means of a link It to an arm ll of a second bell-crank lever which is mounted to swing about the axis of a pivot pin l8, the ends of which are mounted in bosses I9 and 20 (Fig. 4) projecting outwardly from the wall 3 of the casing section a. The link It is pivotally connected to the arm I1 of the bell-crank lever by means of a pivot pin IS. The other arm 2| of this bell-crank lever is linked to the diaphragm 4 by means of the link 22 operatively connected to a plate 22' at the outer side of the diaphragm, as best shown in Fig. A relatively strong coil spring 23 reacts at one end against the arm H of the bell-crank lever |'|--2| through a fulcrum member and guide pin 24, and at itsother end against a washer 25 carried by the end of an adjusting screw 26 (Figs. 4'and The screw 26 turns in a boss 21 which is drilled and threaded to receive it. The opening at the outer end of the boss 21 is normally closed by means of a plug 28. When this plug is removed,

the adjusting screw 26 may be turned by means of a screw driver, the outer end of the screw having a slot 29 for this purpose. In this way the force exerted by the spring 23 on the arm H of the bell-crank lever'|'|-2| may be adjusted.

It will be apparent from the foregoing description that outward movement of the diaphragm 4 by the pressure of the oxygen in the first-stage chamber S1 actuates the bell-crank levers in a direction to move the valve |0 toward its closed position and this action is yieldingly opposed by the coil spring 23. When the pressure in the chamber S1 allows the diaphragm to move inwardly, the bell-crank levers are'moved by the spring 23 in the opposite direction to permit the valve to be moved by the pressure of the incoming oxygen toward its open position. Oxygen admitted through the inlet 1 from a relatively high pressure source is reduced in pressure as it enters the chamber S1 and this chamber remains filled with oxygen: at a predetermined reduced pressure, the diaphragm and its associated parts functioning to close the valve to'stop the admission of oxygen when the predetermined pressure is attained in the chamber S1, and to open the valve and admit more oxygen when the pressure therein falls below the predetermined level.

The section b of the casing is open at its rear but when the sections a and b are fastened together the rear wall 3 of the section a constitutes a closure for the adjoining space in the section b. In other words, the wall ,3 of the section a forms a partition between the firststage oxygen chamber S1 and the adjacent space in the section b. l I

The section b of the casing has a partition 30. The space to the left of this partition, as viewed in Fig. 2, back to the wall 3 of the section a, constitutes a respiratory chamber, or mixing chambor M. A diaphragm 3| closes the opening at the front of the casing section b and forms with the partition 3|! the second-stage oxygen chamber S2. Oxygen is admitted from the first-stage chamber to the second-stage chamber through a port 32 in the inner wall 3 of the first casing section a. This port communicates with a passage 33 (Figs. 1, 2 and 3) which extends through .a boss 34 formed in the casing section b. The passage 33 at its delivery end communicates with the second-stage oxygen chamber S2. The oxygen enters the passage 33 through a port 33 controlled by the second-stage regulating valve 35.. The rod 36 of this valve is pivotally connected to one end of a lever 31 (see also Fig. 10) fulcrumed to the casing at 33. The other'end of the lever 31 is pivotally attached to a spider 39 which bears against the diaphragm 3| (Fig. 2). A relatively light spring 40 acts on the end of lever 31 and the end of rod 33 in a direction which tends to close the valve 35 and force the diaphragm 3| outwardly.

' As best shown in Fig. 10 the spring 40 preferably V gen in the second-stage chamber S2 first passes into a hollow boss or housing 44 extending rearwardly from the partition 30 (Figs. 2 and 6) and then through a port 45 formed in a side wall of the boss and which communicates with the mix ing chamber M. Outside air is admitted to the mixing chamber M through an intake passage 45 (Fig. 6) and a port 41 at the inner end of this passage.

The oxygen port 45 is controlled by an oxygenproportioning valve 48 and the air port 41 is controlled by an air-proportioning valve 49. These valves are adjustably mounted on opposite sides of a common lever 50 pivoted at 5i (Figs. 6 and '7). As shown in these figures the oxygen valve is nearer to the pivot of the lever than the air valve. The lever 50 has attached to it a leaf spring 52, the free end of which engages between two lugs 53 (see also Figs. 8 and 9) projecting from a cam-sleeve 54 mounted on a shaft 55 adapted to be turned a limited distance in one direction or the other by a handle 56 located outside of the casing. As best shown in Figs. 6 and '7 there is a stop 18 on the outsideof. the casing section 2, and a stop 19 on the handle 55 limits the turning movement of the shaft in one direction, while a second stop 60 on the handle limits the turning movement of the shaft in the other direction. A coil spring 8! surrounding the shaft reacts at one end against the casing wall and at its other end against the cam-sleeve 54 to keep the inner surface of the handle 56 pressed against a gasket 82 to provide a fluid-tight seal at this plac When the shaft 55 is turned in a counterclockwise direction, as viewed in Figs. 8 and 9,

and in a clockwise direction as viewed in Fig. l,

the leaf spring 52 is deflected toward the lever and this biases the lever toward the end of an aneroid bellows 51 (Fig, 6). The concentration of the oxygen in the gas in the mixing chamber M will then be varied automatically by the aneroid in accordance with altitude requirements, the arrangement being such that at sea level and for altitudes up to say 5000 feet the air-proportioning valve 40 is fully open and the oxygenproportioning valve 48 is completely closed. At around 5000 feet the aneroid moves the lever 50,

and the air-proportioning valve 49 begins to close and the oxygen proportioning valve 48 begins to open. proportioning valve 48 is gradually opened to a greater extent and the air-proportioning valve is gradually closed to a greater extent until at say 33,000 feet the air-porportioning valve is fully closed. The gas in the mixing chamber M, whether air alone, a mixture of air and oxygen, or pure oxygen, is withdrawn when the aviator inhales, and passes through a port 58 (Fig. 2)

into a passage 59 in a neck portion 60 (see also- Fig. l) which is adapted to be connected to the breathing mask by a suitable hose or conduit. A check valve 6! preferably comprising a light disc of mica or similar material commands the port 58 and is biased closed by a light spring 62.

As the altitude increases, the oxygen- The partition 30 is provided with another port 63 (Figs. 6 and 10) commanded by a valve 64 carried at the end of a light spring arm 65. This valve also preferably comprises a light disc of sleeve 54 deflects the leaf spring 52 away from the lever 50 and this biases the lever away from the end of the aneroid 51 and completely closes the air-proportioning valve 49 and completely opens the oxygen-proportioning valve 48. This may be accomplished by the aviator regardless of altitude and whenever it is desired that pure oxygen be delivered to the breathing mask. When the shaft 55 is turned as just described to open the oxygen-proportioning valve and close the airproportioning valve, a third lug 55 carried by the cam-sleeve 54 (Figs, '1, 8 and 9) engages under and lifts the spring arm 55 to eifectmechanical opening of the oxygen by-pass valve 54 so that there is a full and free supply of oxygen into the mixing chamber M by reason of the fact that both oxygen valves 38 and 54 are then open.

Figs. 6 and 8 show the shaft 55 and cam-sleeve 54 turned by the handle 56 to the position in which oxygen-proportioning valve 08 is biased closed, the air-proportioning valve 49 is biased open, the oxygen by-pass valve 64 is closed, and the lever carrying the valves is and 49 is in position to be automatically controlled by the aneroid. Figs. 7 to 9 show the shaft 55 and camsleeve 54 turned by the handle 56 to the position in which the oxygen-proportioning valve 48 and the oxygen by-pass valve 54 are moved to open position and the air-proportioning valve 49 is moved to closed position.

The oxygen inlet is formed in a casting which has a portion 66 (Fig. 2) extending toward the front of the regulator. The bottom of this casting has a flat seating surface, and as will be seen from Figs. 4, 6 and 10, there is a narrow fiat seat 61 at the top of the casing sections a and b to which the above-mentioned casting may be bolted with a gasket 58 (Fig. 2) intervening. The portion 66' of the casting houses a valve 69 which controls the flow of oxygen through by-pass passages lil from the oxygen inlet to the mixing chamber. As shown in Fig. 2, portions of the by-pass passages are drilled in the casting which casing section b into the mixing chamber. The

valve 59 may be opened or closed by means of a knob ii at the front of the regulator. The valve 69 is normally closed but it'may be opened by the aviator in any emergency in which it is desirable to admit oxygen directly from the oxygen inlet to the mixing chamber and thence to the breathin mask.

In an oxygen regulator, particularly of the type herein disclosed, it is important that the secondstage oxygen regulating valve, or corresponding valve admitting oxygen to a relatively low-pressure chamber, be carefully designed and constructed so that it will work efliciently, and be properly seated by the low-pressure oxygen behind it. The successful operation of this valve depends upon facing its seat-contacting surface with a very thin, smooth and uniform layer of soft rubber. It is not practicable to cement the thin layer of soft rubber to the valve body in the region where the valve contacts with the lip of the valve seat because any cement capable of attaching the thin rubber to the valve body distorts the thin rubber enough tocause leaks. It has been attempted to avoid this difliculty by applying a small droplet of cement at the very center of the valve but then the soft rubber layer was not aflixed firmly enough and it was likely to become detached. Moreover, with this arrangement small particles of foreign material are likely to be caught between the valve body and the rubber facing.

In the improved oxygen regulator herein disfclosed the second-stage regulating valve is free of these objections and disadvantages. As shown in Fig. 3, the body or the valve, which may be substantially in the form of a disc and be made of metal or relatively hard rubber, is provided with a slip-on rubber covering as indicated at 12. This covering is in'the form of an envelop made of thin soft rubber and is slipped over the valve disc so that it embraces the disc and covers the same except where the opening occurs in the rubber envelop at the rear of the valve disc, as indicated in Fig. 3. The rubber envelop is held in place by its own elasticity and is not readily detached. Moreover small particles of foreign matter cannot readily get under the rubber covering', but should they do so the rubber coverin may be easily removed, the surface cleaned, and the covering again slipped on the valve body.

An important feature or the invention is the particular construction of the oxygen-proportioning and air-proportioning valves. As best shown in Figs. 6 and 7 each of these valves l8 and 49 may comprise a thin disc made of mica or similar material. Each of the valve discs is carried by the end of a screw 73 threaded into the lever .50 and locked thereto by means. of a nut ll.

Each of the valve discs may therefore be ad justed relative to the lever which carries it and relative to its valve seat. The outer end of the screw I3 carries a nut against which the valve disc is pressed by means of a spring washer l8.

This washer doesnot bear directly against the valve disc but against a small plate ll interposed between it and the valve disc. The plate 11 of the air-proportioning valve is made slightly thicker than the plate ll of the oxygen-proportioning valve. The diameter of the plate TI is somewhat less than the inside diameter of the port controlled by the valve. Except when the valve disc is rather widely displaced from its seat, thevplate '11 actually enters the port with a small annular clearance. When the valve disc is very close to the valve seat the annular clearance between the walls of the port and the plate ll is so much reater than the clearance between the disc and is largely under the control of the disc. When the disc is displaced its maximum distance from the valve seat the displacement is so much greater greatest for intermediate positions of the valve disc. The effect 01 the throttling plate ll-Lia to the lip of the valve seat that the discharge of gas introduce relatively high resistances to the flow of air into the mixing chamber at the lower altitudes. The diameter of the seat lip at the end of the air port may therefore be greater than otherwise, and as a result a better control may be eiiected on oxygen concentration for altitudes around 25,000 feet.

An oxygen regulator of the type herein disclosed could no doubt be designed so that the suction in the mixing chamber is suflicient to give the proper oxygen concentration for all altitudes without the use of a throttling plate on the airproportioning valve as just described, provided the apparatus is free from air leaks. However, air leakage is sometimes unavoidable and this will decrease the suction in the mixing chamber. It so happens that in oxygen regulators of the general type herein disclosed, the suction in the mixing chamber for intermediate altitudes is such that the pressure in this chamber is usually not much less than the pressure in the second-stage chamber S2. An air leak may have a relatively insignificant effect in decreasing oxygen concentration as a direct result of the leak if 7 there is -pressure in the second-stage oxygen chamber then the eilect of the leak becomes serious in that the oxygen induction into the mixing chamber tends to cease and as a consequence the amount of air admitted by'the air-proportioning valve will increase. The throttling plate on the air-proportioning'valve restricts the flow of air into the mixing chamber at intermediate altitudes and therefore insures a sufficient oxygen concentration at the intermediate altitudes. The oxygen concentration when the regulator has an air leak of say .169" in diameter is, in general, considerably lower when no throttling plate is employed on the air-proportioning valve than when the throttling plate is used, or for the same minimum oxygen concentration in the inspired air, the throttling of the air at intermediate altitudes permits breathing when there is a leak of say .194" in diameter instead of a leak of only .169" in diameter. In other words, the area of the leak may be increased 40%.

The danger of low oxygen concentration at low altitudes is negligible. Consequently the regulator herein disclosed is so designed that at very low altitudes, the inspiratory resistances will be low without any danger of seriously afl'ecting the oxygen concentration in event of a mask leak. Moreover, the inspiratory resistances should be low at very low altitudes because when operating with the automatic mixing mechanism thrown out of operation, the oxygenconsumptions, close to sea level when doing heavy work, are so great that there is a serious tendency for the inspiratory resistances during denitrogenatlon" to become so great as to be insufferable. This tendency has been minimized in the regulator herein disclosed through the use of the above described automatic oxygen by-pass valve which may be opened by means of the handle 56 during denitrogenation.

' It will now be seen that the regulator is very compact in construction and this is due at least in part to the location of the operating parts or the first-stage chamber, including the spring 23, at the inner side of the diaphragrm 4, i. e., within the first-stage chamber itself. The improved construction of the second-stage regulating valve and the oxygen-proportioning and air-proportioning valves improves the operation of the regulater as above pointed outrand such parts'as the automatic oxygen by-pass valve, the emergency by-pass valve, and the mechanism operable by the aviator for throwing the-automatic mixing mechanism for the oxygen and air into and out of operation and for positively opening the automatic oxygen by-pass valve, provide desirable safety features for the regulator and add to its usefulness and convenience of operation by the aviator, and in general make it a more satisfactory regulator.

I claim:

1. An oxygen regulator for avia'tors comprising a respiratory chamber, an oxygen chamber, a valve-controlled port through which oxygen may be drawn into the respiratory chamber from the oxygen chamber upon inhalation by the aviator,

and a valve-controlled port through which air may be drawn into the respiratory chamber upon inhalation by the aviator, each of said valves having means effective only for intermediate open positions of the valve for increasing the amount of throttling action that would be obtained by the valve at such intermediate open positions in the absence of said means.

3. An oxygen regulator for aviators comprising a respiratory chamber,. an oxygen chamber, a

valve-controlled port through which oxygen may be drawn into the respiratory chamber from the oxygen chamber upon inhalation by the aviatior,

a port through which air may be drawn into the respiratory chamber upon inhalation by the aviator, an air valve controlling said last-named port and comprising a thin disc, a seat encircling the exit end of the air port and against which one side of said disc is adapted to seat, and a throttling plate at said side of the disc, said plate being of smaller diameter than the inside diameter. of the air port and being adapted to project into the air port with a small annular clearance except when the disc is widely displaced from its seat at which time said plate lies entirely outside of the air port.

4. An'oxygen regulator for aviators comprising a respiratory chamber, an oxygen chamber, a valve-controlled port through which oxygen may be drawn into the respiratory chamber from the oxygen chamber upon inhalation by the aviator, a valve-controlled port through which air may be drawn into the respiratory chamber upon inhalation by the aviator, each of said valves comprisinga thin disc and each disc cooperating with seat, each of the said plates being of smaller diameter than the inside diameter of the corresponding port and being, adapted to project into the corresponding port with a small annular clearance except when the disc carrying it is 10 f widely displaced from its seat at which time the plate lies entirely outside of the port.

5. An oxygen regulator in accordance with claim 4 in which the plate on the valve-disc for the air port is thicker than the plate on the valve disc for the oxygen port.

6. An oxygen regulator for aviators comprising -a respiratory chamber, an oxygen chamber, a

valve-controlled port through which oxygen may be drawn into the respiratorychamber from the oxygen chamber upon inhalation by the aviator, a valve-controlled port through which air may be drawn into the respiratory chamber upon inhalation by the aviator, and an aneroid which regulates the opening of the air valve in accordance with the altitude, the air valve having means eflective only for intermediate open positions of the valve for increasing the amount of throttling action that would be obtained by the valve at such intermediate open positions and for intermediate altitudes in the absence of said means.

7. An oxygen regulator for aviators comprising a respiratory chamber, an oxygen chamber, a valve-controlled port through which oxygen may be drawn into the respiratory chamber from the oxygen chamber upon inhalation by the aviator, a valve-controlled port through which air may be drawn into the respiratory chamber upon inhalation by the aviator, and an aneroid which regulates the opening of the air valve and the oxygen valve in accordance with the altitude, theair valve having means effective only for intermediate open positions of the valve for increasing the amount of throttling action that would be obtained by the valve at such intermediate open positions and for intermediate altitudes in the absence of said means.

8. An oxygen regulator for aviators comprising a respiratory chamber, an oxygen chamber, a valve-controlled port through which oxygen may be drawn into the respiratory chamber from the oxygen chamber upon inhalation by the aviator, a valve-controlled port through which air may be drawn into the respiratory chamber upon inhalationby the aviator, and an aneroid which regulates the opening of the air valve and the oxygen valve in accordance with the altitude, the

a valve-controlled port through which air maybe drawn into the respiratory chamber upon inhalation by the aviator, and a pivoted lever on which both the oxygen valve and the air valve are mounted so that movement of the lever moves one of the valves toward closed position and the other valve toward open position.

10. An oxygen regulator in accordance v with claim 9 in which one of the valves is mounted on the lever closer to the pivot of the lever than the other valve.

11. An oxygen regulator for aviators comprising a respiratory chamber, an oxygen chamber,

a valve-controlled port through which oxygen may be drawn into the respiratory chamber from the oxygen chamber upon inhalation by the aviator, avalve-controlled' port through which air essence it may be drawn into the respiratory chamber upon inhalation by the aviator, and means manually operable by the aviator and operstively connected to both valves for mecheuicclly and positively closing the air valve and simultaneously opening the oxygen valve.

12. An oxygen regulator for aviators comprising a. respiratory chamber, on oxygen chamber, a. port through which oxygen may be drawn into the respiratory chamber from the oxygen chamber upon inhalation by the svietor, on oxygenproportlonlng volve controlling said port, a. port through which sir may be drawn into the res piratory chamber upon inhalation by the aviator, an eir-proportioulng valve controlling the sir port, s check. valve constituting an oxygen by= pass vslve opening toward said respirotory chambet, and means operable by the evietor for closing the eir-propcrtioriing value and for simultsneously opening the oxygen proportloning valve and said oxygen by-poss valve.

13. en oxygen regulator for sviotors comprising or respiratory chamber, on oxygen chamber,

the oxygen chamber upon inhalation by the eviator, e vslvewontrolled port through which cir may be drown into the respiretory chamber upon inhalation by the cvictor, on, cues-old device adapted to automatically control the position of the sir valve in cccordsnce with the altitude, end means operable by the aviator for either placing the air valve under the outometic control of the aneroid device or discontinuing the influence of the cnerolci device upon the air valve.

14. An oxygen regulator for aviators comprising a respiratory chamber, an oxygen chamber, a valve-controlled port through which oxygen may be drawn into the respiratory chamber from the oxygen chamber upon inhalation by the aviator, a valve -controlled port. through which air may be drawn into the respiratory chamber upon inhalation by the aviator, en ancroicl device adapted to automatically control the position of the air valve and the oxygexrvelve in accordance with the altitude, and meats operable by the aviator foreither placing the air valve and oxygen valve under the automatic control of the aneroid device or discontinuing the influence of the anerold device upon said valves.

15. An oxygen regulator for aviators comprising a. respiratory chamber, an oxygen chamber,

a valve-controlled port through which oxygen may be drawn into the respiratory chamber from the oxygen chamber upon inhalation by the eviator, a valve-controlled port through which air may be drawn into the respiratory chamber upon inhalation by the aviator, a pivoted lever on which both the oxygen valve and the air valve are mounted, on aneroid device adapted to act on said lever to adjust the position. of the two ing a. respiratory chamber, on oxygen chamber,

a. valve-controlled port through which oxygen may be drawn into the respiratory chamber from the oxygen chamber upon inhalation by the avistor, a valve-controlled port through which air may be drown into the respiratory chamber upon inhalation by the ovictor, a pivoted lever on which the air valve is mounted, on enerold device adapted to set on said lever to adjust the position of the air valve in cccordcnce with the altitude, and means operable by the aviator for moving said lever to one position in which it is under the influence of the eneroid device or to another position in which it is out of the influence of the sneroid device.

l7. An oxygen regulator for aviators comprising s. respiratory chamber, valves for admitting oxygen end air to the respiratory chamber upon inhalation by the evistor, means responsive to changes in atmospheric pressure for automaticelly controlling the position of said valves so that the oxygen concentration in the gas mixture in the respiratory chamber is varied automatically in accordance with altitude requirements, and means operable by the aviator for either placing said valves under the automatic control of said firstmemed means or discontinuing the influence of said means upon said. valves.

18. An oxygen regulator for aviators comprising it respiratory chamber, an oxygen chamber, a port through which oxygen may be drawn into the respiratory chamber from the oxygen chamber upon inhalation by the aviator, on oxygenproporticnlug valve controlling sold port, a part through which an. may be drawn into the respiratory chamber upon inhalation by the aviator, an

sir-proportioning valve controlling-said port, e pivoted lever on which both the oxygen-propcv.

tionlng valve and the clr-proportlonlng valve are mounted, on snerold device adapted to act on said lever to edjust the position of the two valves in accordance with the altitude, a check. valve constituting on oxygen by-psss vclve opening toward the respiratory chembcr, and meansoperable by the aviator for moving said lever to one position in which it is under the influence of the aneroid device or to s, second position in which it is out of the influence of the eneroid. device and in which the alr-proportiouing valve is closed and the oxygen-proportioning valve is open, and means operating when the lever is moved to said second position to mechanically open said oxygen bypass valve.

GEOE M. DEMING. 

